JP2019100359A - Sealing device - Google Patents

Abstract

To suppress deterioration of sealability, in a sealing device having an energization member for energizing a lip part.SOLUTION: A sealing device comprises: a seal body 10 that has an annular trunk body part 18, an outer peripheral base part 12 extending from the trunk body part 18 to a radially outward side and an external side (A), and an elastic body-based lip part 13 configured to extend from the trunk body part 18 to the radially outward side and the external side to contact with an outer peripheral surface of a shaft 200, and that is mounted on an inner peripheral surface of a housing 300; and an energization member 20 that is provided in an annular groove 17 formed by the outer peripheral base part 12, the trunk body part 18 and the lip part 13 of the seal body 10, and that energizes the lip part 13 toward the outer peripheral surface of the shaft 200. In the lip part 13, a plurality of slits 15 is provided at intervals in a circumferential direction so as to penetrate an outer peripheral surface 133 and inner peripheral surface 134 of the lip part 13 and extend from a tip 132 of the external side (A) toward an equipment internal side (M).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sealing device used as a dust seal or the like around a shaft of a hydraulic cylinder device or the like.

  A dust seal using an elastic material such as rubber, urethane, PTFE (polytetrafluoroethylene), or resin is used as a sealing device for suppressing the entry of foreign matter into the device from the outside. In a dust seal that is required to have the function of scraping off dust that has adhered to a shaft, high rigidity is required for the seal lip, and rubber, urethane, resin, or the like with high hardness is used as the material of the dust seal. However, since there is a problem that plastic deformation (swelling) occurs in the dust seal due to creep or deterioration, and the sealability is reduced, a technique for maintaining the sealability for a long time is required.

  Therefore, a technique is known in which a seal lip is kept in close contact with the outer peripheral surface of the shaft and the inner peripheral surface of the housing by mounting a metal spring in an annular mounting groove formed in the seal body. (See, for example, Patent Document 1). FIG. 9 shows such a prior art. The annular packing 96 mounted in the annular groove 93 provided in the piston 91 is formed with an annular groove 94 having a substantially U-shaped cross section opened in the axial direction, and the seal lip 951 contacting the groove bottom of the annular groove 93 And a seal lip 952 in contact with the inner circumferential surface of the cylinder 92. An annular spring 98 having a substantially V-shaped cross section is mounted in the annular groove 94, and urges the seal lips 951 and 952 radially inward and outward. Due to the biasing force of the spring 98, even if the elastic material such as PTFE constituting the packing is deformed, the interference of the seal lips 951, 952 can be maintained.

  However, if an excessive load is applied to the dust seal having such a spring due to interference with the shaft end face when mounted on the equipment used or excessive eccentricity of the shaft, etc., the spring is plastically deformed and a seal lip is attached. The ability to turn on may be reduced. Then, there is a problem that it is difficult to maintain the tightness of the seal lip and the sealability is reduced.

Japanese Utility Model Publication No. 63-27763

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of suppressing a decrease in sealability in a sealing device having a biasing member that biases a lip portion.

The present invention adopts the following means in order to solve the above problems.
That is, the sealing device of the present invention is
A sealing device for sealing an annular gap between a shaft and a housing to prevent dust from entering the device from the outside,
An annular body, an outer peripheral base extending radially outward and outward from the body, and an elastic body extending radially inward and outward from the body and contacting the outer peripheral surface of the shaft A seal body having a lip portion and attached to an inner circumferential surface of the housing;
An urging member provided in an annular groove formed by the outer peripheral base of the seal body, the body portion and the lip portion, and urging the lip portion toward the outer peripheral surface of the shaft;
Equipped with
The lip portion is characterized in that a plurality of slits extending through the outer peripheral surface and the inner peripheral surface of the lip portion and extending from the outer end to the device inner side are provided at intervals in the circumferential direction. .

  According to the sealing device configured as described above, the rigidity of the lip portion is lowered by providing the plurality of slits in the lip portion, and the lip portion is largely deformed even if the urging force of the urging member is small. Can. Therefore, the lip portion can be reliably brought into close contact with the outer peripheral surface of the shaft, and even when the biasing member having a small biasing force is used, the interference of the lip portion can be secured over a long period of time. And the decrease in sealability can be suppressed.

  In the present invention, the slit may be provided at an angle to the axial direction.

  As a result, it is possible to prevent foreign matter from invading the inside of the device from the outside through the slit.

  In the present invention, in the lip portion, the circumferential length in the contact surface of the lip portion with the axis excluding the total of the circumferential widths of the plurality of slits is equal to or less than the circumferential length of the outer peripheral surface of the axis It should be designed as

  Thereby, in a state where the sealing device is mounted and the lip portion is in close contact with the outer peripheral surface of the shaft by the biasing force of the biasing member, the gap generated due to providing the slit in the lip portion is small Become. Therefore, it is possible to prevent foreign matter from invading the inside of the device from the outside through the slit.

  In the present invention, the angle between the lip and the outer peripheral surface of the shaft with which the lip is in contact is preferably larger at the outer side than at the inner side of the device.

  Thereby, the surface pressure on the seal surface between the lip portion and the outer peripheral surface of the shaft becomes larger on the outside side. Therefore, when the shaft reciprocates relative to the housing, high sealing performance against liquid dust is obtained.

  In the present invention, the biasing member may be a coil spring that biases the lip inward in the radial direction.

  Since the coil spring has a property that plastic deformation does not easily occur, by using the coil spring as the biasing member, even if a large load is applied to the biasing member due to attachment of the sealing device or excessive eccentricity of the shaft, etc. It is possible to suppress the decrease in sealability of the sealing device due to plastic deformation. Depending on the size of the seal body, it is difficult to increase the elastic force (tension force) of the coil spring. However, a slit is provided in the lip portion where the coil spring presses inward in the radial direction, and the rigidity of the lip portion is low, so that the lip portion can be sufficiently deformed even if the elastic force of the coil spring is small. Therefore, while being able to suppress a fall of sealing performance, it can also control that an energizing member is plastically deformed by the load which acts on a sealing device.

  In the present invention, the biasing member has a bent end, an outer peripheral pressing portion extending radially outward from the end and pressing the inner peripheral surface of the outer peripheral base, and radially inward from the end. It is good if it is a metal leaf | plate spring which has and the inner peripheral pressing part which extends and presses the outer peripheral surface of the said lip | rip part.

  The substantially V-shaped or U-shaped metal plate spring configured in this manner has a length from one end to the end of the inner peripheral pressing portion and a length from one end to the end of the outer peripheral pressing portion (axis By lengthening the length in the direction and shortening the length (radial length) from one end of the inner circumferential pressing portion to one end of the outer circumferential pressing portion, plastic deformation is less likely to occur, and the radial length is It can be designed to be elastically deformed even to almost zero deformation. Therefore, even if a large load is applied to the biasing member due to mounting of the sealing device or excessive eccentricity of the shaft or the like, it is possible to suppress deterioration in sealing performance of the sealing device due to plastic deformation of the biasing member. Here, if the axial length of the leaf spring is increased and the radial length is shortened, the elastic force (tension force) of the leaf spring is reduced. However, since the lip is provided with a slit and the leaf spring presses inward in the radial direction, and the rigidity of the lip is low, the lip can be sufficiently deformed even if the elastic force of the spring member is small. Therefore, while being able to suppress a fall of sealing performance, it can also control that an energizing member is plastically deformed by the load which acts on a sealing device.

  The above-described configurations may be combined and used as much as possible.

  According to the present invention, in the sealing device having a spring member that biases the lip portion, it is possible to suppress the decrease in sealing performance.

FIG. 1 is a schematic cross-sectional view of a sealing device according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the mounted state of the sealing device according to the first embodiment of the present invention. FIG. 3 is a perspective view of the sealing device according to the first embodiment of the present invention. FIG. 4 is an enlarged perspective view of a part of the sealing device according to the first embodiment of the present invention. FIG. 5 is a schematic cross-sectional view taken along the line BB of FIG. 1 of the sealing device according to the first embodiment of the present invention. FIG. 6 is an enlarged perspective view of a part of a sealing device according to a second embodiment of the present invention. FIG. 7 is a schematic cross-sectional view of the sealing device according to the second embodiment of the present invention taken along the line BB in FIG. FIG. 8 is a schematic cross-sectional view of a sealing device according to a third embodiment of the present invention. FIG. 9 is a diagram for explaining the prior art.

  Hereinafter, with reference to the drawings, modes for carrying out the present invention will be exemplarily described in detail based on examples. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. .

  A sealing device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. The sealing device according to the present embodiment is a mechanism in which the shaft and the housing move relative to each other, such as hydraulic cylinders and suspensions of automobiles, construction machines, general industrial machines, etc., from outside, earth and sand, ore, oil, water, It can apply suitably to the dust seal which controls that foreign substances (dust), such as ice and sap, enter into an apparatus. In addition, the sealing device according to the present embodiment is also applicable to the case where the shaft reciprocates relative to the housing, rotates relative to the housing, pivots relative to the housing, and any combination thereof. It can apply. In the following description, an axis means the central axis of the axis.

Example 1
FIG. 3 is a perspective view showing the overall shape of the sealing device 100 according to the first embodiment. As shown in FIG. 3, the sealing device 100 is annular and has a rotationally symmetrical shape. A schematic cross-sectional view by a cross section (AA cross section in FIG. 3) according to a plane including the rotational symmetry axis of the sealing device 100 is shown in FIG. In FIG. 1, in the sealing device 100, the seal body 10 made of an elastic body, the metal plate spring 20 disposed in a state of being prevented from coming off in the annular groove 17 of the seal body 10, and the seal body 10 are integrated. And a reinforcing ring 14 provided.

  As shown in FIG. 2, the sealing device 100 is held by an annular mounting groove 310 provided on the inner peripheral surface of the end member 320 of the cylinder 300 into which the shaft 200 is inserted. An annular gap between the inner circumferential surface and the inner circumferential surface is sealed, dust is prevented from entering from the outer side (A) on the right side in the figure to the device inner side (M) on the left side in the figure, It also plays the role of scraping off attached dust. The seal body 10 is fixed to the cylinder 300 by being mounted in the mounting groove 310. When the shaft 200 reciprocates in the axial direction relatively to the cylinder 300, the seal body 10 slides on the outer peripheral surface of the shaft 200.

  The seal body 10 is made of PTFE, rubber, urethane, resin or the like, and has a rotationally symmetrical shape. The seal body 10 has an annular body portion 18, an outer peripheral base 12 extending radially outward and outward (A) from the body portion 18, and a shaft 200 extending radially inward and outward (A) from the body portion 18. And an elastic lip portion 13 configured to be in contact with the outer peripheral surface of the frame, and the cross section of the plane including the axis line is substantially U-shaped.

  The outer peripheral base 12 is joined to the inner circumferential surface of the cylindrical portion 141 of the reinforcing ring 14, and the body portion 18 is joined to the inner side surface of the flange portion 142 of the reinforcing ring 14. The outer circumferential base portion 12 is provided with an annular protrusion 121 projecting radially inward at a tip end in the axial direction in order to suppress the falling of the plate spring 20. An annular groove 17 formed by the outer peripheral base portion 12, the body portion 18 and the lip portion 13 of the seal main body 10 has a substantially U-shaped cross section opened outward.

  A tip 131 in close contact with the outer peripheral surface of the shaft 200 of the lip portion 13 is formed as a sharp lip or a minute R lip (for example, R 0.1 to R 0.2). An inner circumferential surface 135 of the outer side (A) of the lip portion 13 with an angle α between the inner circumferential surface 134 of the device inner side (M) of the lip portion 13 and an outer circumferential surface of the shaft 200 with which the lip portion 13 contacts. The angle β with the outer peripheral surface of the shaft 200 with which the lip portion 13 contacts is larger.

  The leaf spring 20 is an annular leaf spring mounted in the annular groove 17 of the seal body 10 and made of a thin plate of metal such as stainless steel. The leaf spring 20 biases the lip portion 13 toward the outer peripheral surface of the shaft 200. The leaf spring 20 has an end 23 located along the groove bottom of the annular groove 17 and an outer peripheral pressing portion 21 extending radially outward from the end 23 and pressing the inner peripheral surface of the outer peripheral base 12 of the seal body 10. , And an inner peripheral pressing portion 22 extending radially inward from the end portion 23 to press the outer peripheral surface of the lip portion 13 of the seal main body 10, and a cross section by a plane including the axis is substantially V-shaped or U-shaped I The tip end 211 of the outer side (A) of the outer peripheral pressing portion 21 of the leaf spring 20 is engaged with a protrusion 121 for preventing the leaf spring 20 provided at the tip of the outer side (A) of the outer peripheral base 12.

  In the state before the leaf spring 20 is incorporated into the seal main body 10, that is, in the free state, as shown in FIG. 1, the radial distance L2 between the tip 211 of the outer circumferential pressing portion 21 and the tip 221 of the inner circumferential pressing portion 22 Is larger than the radial distance L1 between the protrusion 121 of the outer peripheral base 12 of the seal body 10 and the tip 132 on the outer peripheral side of the lip portion 13. Therefore, the plate spring 20 is radially compressed and elastically deformed in a state of being incorporated in the annular groove 17 of the seal main body 10, and the outer circumferential pressing portion 21 is the inner periphery of the outer circumferential base 12 by the elastic force generated thereby. While pressing the surface radially outward, the inner peripheral pressing portion 22 presses the outer peripheral surface of the lip portion 13 radially inward.

  The leaf spring 20 is such that the radial length L1 in the state of being incorporated in the annular groove 17 of the seal main body 10 is shorter than the axial length L3 of the outer peripheral pressing portion 21 and the inner peripheral pressing portion 22. I'm designing.

  The reinforcing ring 14 is made of a high rigidity material such as metal, and has a cylindrical portion 141 and a flange portion 142 extending inward in the radial direction from one end in the axial direction of the cylindrical portion 141. I The outer diameter of the cylindrical portion 141 is slightly larger than the inner diameter of the mounting groove 310 of the end member 320 of the cylinder 300 shown in FIG. 2 and can be press-fit into the mounting groove 310 with an appropriate interference.

  The perspective view which expanded a part of sealing device 100 is shown in FIG. Further, FIG. 5 is a schematic cross-sectional view of a cross section (BB cross section of FIG. 1) taken along a plane parallel to the circumferential direction of the sealing device 100. The plate spring 20 is not shown in FIGS. 4 and 5. As shown in FIGS. 4 and 5, the lip 13 of the seal body 10 of the sealing device 100 of the first embodiment penetrates the outer peripheral surface 133 and the inner peripheral surface 134 of the lip 13 and is the tip of the outer side (A). A plurality of slits 15 extending from 132 to the device inner side (M) are provided at intervals in the circumferential direction. The seal body 10 having the slits 15 is manufactured by injection molding or cutting.

  The lip portion 13 is designed such that the circumferential length of the lip portion 13 excluding the sum W × N (N is the number of slits) of the circumferential widths W of the plurality of slits 15 is equal to or less than the circumferential length of the shaft 200 Ru. That is, the inner diameter of the lip portion 13 is designed to be larger than the outer diameter of the shaft by the width of the slit in the circumferential direction.

<Excellent points of the sealing device according to the first embodiment>
In the sealing device 100 of the first embodiment described above, the plate spring 20 is V-shaped, and is designed such that the radial length L1 is shorter than the axial length L3. In the V-shaped plate spring 20, when the radial length L1 is shortened with respect to the axial length L3, the radial length L1 of the plate spring 20 is compressed to a length close to zero. Even if it receives such deformation, it can be designed to be elastically deformed without plastic deformation. As a result, the radial length L1 of the leaf spring 20 is compressed to a length close to zero due to interference with the shaft 200 when mounting the sealing device 100 on the cylinder 300, excessive eccentricity of the shaft, or the like. Even if it exists, since it can suppress that the plate spring 20 carries out plastic deformation, it can suppress that the function to which the plate spring 20 presses the lip part 13 falls.

  Here, when the radial length L1 of the V-shaped plate spring 20 is shorter than the axial length L3, the elastic force (tension force) of the plate spring 20 is reduced. Therefore, the amount by which the plate spring 20 presses the lip portion 13 toward the shaft 200 to deform it is reduced.

  In this respect, in the sealing device 100 according to the first embodiment, the lip portion 13 has a slit 15 extending from the outer side (A) to the device inner side (M) so as to penetrate the outer peripheral surface 133 and the inner peripheral surface 134 of the lip portion 13. Since a plurality is provided at intervals in the circumferential direction, the rigidity of the lip portion 13 is low. Therefore, even if the tension force of the plate spring 20 is small, the lip portion 13 can be largely deformed. Therefore, the lip portion 13 can be reliably brought into close contact with the outer peripheral surface of the shaft 200, and the reduction in sealing performance of the sealing device 100 can be suppressed. As described above, according to the sealing device 100 of the first embodiment, it is possible to suppress plastic deformation of the leaf spring 20 when an excessive load is applied to the sealing device 100 at the time of shaft attachment or the like, and Even if the pressure force of 20 is small, the sealing performance of the sealing device 100 can be secured.

Further, in the sealing device 100 according to the first embodiment, although the plurality of slits 15 are provided in the lip portion 13 in order to lower the rigidity of the lip portion 13, the total of the circumferential widths of the plurality of slits 15 is excluded. Since the circumferential length of the lip 13 is designed to be equal to or less than the circumferential length of the shaft 20, the sealing device 100 is mounted on the cylinder 300 and the lip 13 is applied to the outer circumferential surface of the shaft 200 by the tension force of the plate spring 20. In the closely-contacted state, the circumferential gap of the slit 15 can be a small value close to zero. Thereby, even if the slits 15 are provided, it is possible to suppress dust from intruding into the device inner side (M) from the outside (A).

  Further, in the sealing device 100 according to the first embodiment, since the tip end 131 of the lip portion 13 is formed as a sharp lip or a minute R lip, the contact width between the lip portion 13 and the shaft 200 is reduced. As a result, even if the tension force of the plate spring 20 is small, the contact pressure on the seal surface is increased, the sealability is improved, and it is possible to scrape off the dust adhering to the outer peripheral surface of the shaft 200.

  Further, in the sealing device 100 of the first embodiment, the outer side (A) of the lip portion 13 with respect to the angle α formed by the inner peripheral surface 134 of the lip portion 13 on the device inner side (M) and the outer peripheral surface of the shaft 200. Of the seal surface in the case where the maximum value of the surface pressure on the seal surface is located on the outer side (A) and the shaft 200 reciprocates Surface pressure gradient becomes large. As a result, when the shaft 200 and the cylinder 300 relatively reciprocate in the axial direction, the liquid film can be made thinner with respect to liquid dust, so that good sealability with respect to liquid dust can be obtained.

(Example 2)
Next, a second embodiment of the present invention will be described. Hereinafter, differences from the first embodiment will be mainly described, and detailed descriptions of matters in common with the first embodiment will be omitted.

  The second embodiment differs from the first embodiment in the shape of the slits provided in the lip portion 13. The perspective view which expanded a part of sealing device 101 which concerns on Example 2 is shown in FIG. Further, FIG. 7 is a schematic cross-sectional view of a cross section (BB cross section of FIG. 1) taken along a plane parallel to the circumferential direction of the sealing device 101. The plate spring 20 is not shown in FIGS. 6 and 7. As shown in FIGS. 6 and 7, in the lip portion 13 of the seal body 11 of the sealing device 101 of the second embodiment, the outer peripheral surface 133 and the inner peripheral surface 134 of the lip portion 13 are pierced from the outer side (A). A plurality of slits 16 extending to the device inner side (M) are provided at intervals in the circumferential direction, and the slits 16 are different from the first embodiment in that they are provided at an angle with respect to the axial direction. The fact that the slits 16 are provided at an angle to the axial direction means that the slits 16 are not parallel to the plane containing the axis.

<Excellent points of the sealing device according to Example 2>
Since the slits 16 are provided at an angle to the axial direction, the flowability in the axial direction is reduced, so foreign matter intrudes into the inside (M) of the apparatus from the outside (A) through the slits 16 Can be suppressed.

  In the first embodiment, an example has been described in which the slit 15 and the lip portion 13 are designed such that the circumferential length of the lip portion 13 excluding the total of the circumferential widths of the plurality of slits 15 is equal to or less than the circumferential length of the shaft 20. Even if designed in this way, it may be difficult to make the circumferential gap of the slit 15 always as small as zero in the mounted state of the sealing device 100 due to tolerances and temperature changes. In this respect, according to the second embodiment, since the slits 16 are provided at an angle in the axial direction, even if the clearance in the circumferential direction of the slits 16 becomes somewhat large due to a temperature change, etc. It is possible to suppress the decrease.

(Example 3)
Next, a third embodiment of the present invention will be described. Hereinafter, differences from the first embodiment will be mainly described, and detailed descriptions of matters in common with the first embodiment will be omitted.

  FIG. 8 is a schematic cross-sectional view of a sealing device 102 according to a third embodiment of the present invention. As shown in FIG. 8, in the sealing device 102 according to the third embodiment, a coil spring 40 is provided in the annular groove 17 of the seal main body 10 instead of the plate spring 20 of the first embodiment. The coil spring 40 is mounted in a mounting groove 123 provided on the inner peripheral surface 122 of the outer peripheral base 12 of the seal main body 10 so as to bias the lip portion 13 of the seal main body 10 radially inward.

<Superior points of the sealing device according to the third embodiment>
The coil spring 40 has a wide elastic range with respect to the amount of extension (the amount extended from the free length of the spring), and the coil cross section has high rigidity and is unlikely to be plastically deformed. By using the spring 40, even when a large load is applied to the coil spring 40 due to attachment of the sealing device 102 or excessive eccentricity of the shaft 200, etc., it is possible to suppress a decrease in sealing performance of the sealing device 102.

  Depending on the size of the seal body 10, it is difficult to increase the elastic force (tension force) of the coil spring 40, but the slit described in the first embodiment is in the lip portion 13 pressed radially inward by the coil spring 40. Since the slit 16 described in 15 or the second embodiment is provided and the rigidity of the lip portion 13 is low, the lip portion 13 can be deformed even if the tension force of the coil spring 40 is small. Therefore, while being able to suppress the fall of sealing performance, it can also suppress that the coil spring 40 is plastically deformed by the load which acts on the sealing device 102.

  Also in the case of the third embodiment, as described in the first embodiment, the tip 131 of the lip portion 13 is a sharp lip or a minute R lip so that the surface of the seal surface is small even if the tension force of the coil spring 40 is small. The pressure can be increased.

(Modification)
In each of the above embodiments, the sealing device is mounted in the mounting groove of the inner peripheral surface of the cylinder, and the example of the sealing structure in which the inner peripheral side of the sealing device contacts the outer peripheral side of the shaft to seal is described. The present invention can also be applied to a sealing structure in which a sealing device is mounted in a mounting groove provided on an outer peripheral surface, and the outer peripheral side of the sealing device contacts the inner peripheral side of the cylinder to seal. In that case, the seal body of the sealing device is provided with a lip on the outer peripheral side, and the lip is provided with a slit. As a result, the rigidity of the lip portion is reduced, so that the lip portion can be easily deformed even if the elastic force outward in the radial direction by the V-shaped plate spring or coil spring mounted in the mounting groove of the seal body is small. Therefore, even if a coil spring or a V-shaped plate spring with a long axial length is used to suppress plastic deformation due to an excessive load, the sealing performance of the lip is reduced by the elastic force of the plate spring or the coil spring. Can be obtained.

10: seal body 100: sealing device 101: sealing device 102: sealing device 11: seal main body 12: outer peripheral base 121: projection 122: inner peripheral surface 123: mounting groove 13: lip portion 131: tip 132: tip 132: tip 133: outer surface 134: inner circumferential surface 135: inner circumferential surface 14: reinforcing ring 141: cylindrical portion 142: flange portion 15: slit 16: slit 17: annular groove 18: body portion 20: leaf spring 200: shaft 21: outer circumferential pressing portion 211: Tip 22: Inner circumference pressing part 221: Tip 23: End 300: Cylinder 310: Mounting groove 320: End member 40: Coil spring

Claims (6)

A sealing device for sealing an annular gap between a shaft and a housing to prevent dust from entering the device from the outside,
An annular body, an outer peripheral base extending radially outward and outward from the body, and an elastic body extending radially inward and outward from the body and contacting the outer peripheral surface of the shaft A seal body having a lip portion and attached to an inner circumferential surface of the housing;
An urging member provided in an annular groove formed by the outer peripheral base of the seal body, the body portion and the lip portion, and urging the lip portion toward the outer peripheral surface of the shaft;
Equipped with
The lip portion is characterized in that a plurality of slits extending through the outer peripheral surface and the inner peripheral surface of the lip portion and extending from the outer end to the device inner side are provided at intervals in the circumferential direction. Sealing device.   The sealing device according to claim 1, wherein the slit is provided at an angle to the axial direction.   The lip portion is designed such that the circumferential length at the contact surface of the lip portion with the shaft excluding the sum of the circumferential widths of the plurality of slits is equal to or less than the circumferential length of the outer peripheral surface of the shaft The sealing device according to claim 1 or 2.   The angle between the inner peripheral surface of the lip portion and the outer peripheral surface of the shaft contacting the lip portion is larger at the outer side than at the inner side of the device. Sealing device.   The sealing device according to any one of claims 1 to 4, wherein the biasing member is a coil spring that biases the lip inward in the radial direction.   The biasing member has a bent end, an outer peripheral pressing portion extending radially outward from the end to press the inner peripheral surface of the outer peripheral base, and extending radially inward from the end and the lip The sealing device according to any one of claims 1 to 4, wherein the sealing device is a metal plate spring having an inner peripheral pressing portion for pressing the outer peripheral surface thereof.